More efficient conditioning

[barneydobson]

pygeoflood looks good especially for conditioning high resolution data, e.g., here

This issue can also group together:

• Use RichDEM for conditioning #137
• Downsample for prettier catchment outlines #138

Since all are related to conditioning

[tijanajovanovic]

Whitebox GAT gives good results when doing hydrological analysis from lidar data. One big problem with it is it can't load the dataset from a numpy array or xarray. The dem needs to be opened from a local folder with their own function (read_raster) that creates a dataset type raster. On the positive side, whitebox is self contained and it doesn't depend on external functions. Only the ones that they have control of and know how they work... but it does mean that it is not compatible with other packages... so one would need to save outputs (tif or shapefile) to be able to combine with other packages like geopandas and rasterio...